Jython's current fragility means that the next release will primarily
be a cleanup release. The current plan is to target Python 2.5.

We have noticed that the current codebase is
extremely brittle and uses way to many different styles to do many of
the same things. All of this inconsistency makes bugfixing a
nightmare, and makes learning the codebase from scratch
extraordinarily difficult.

This means that, at least for the core developers, we will be
concentrating on making a clean 2.5, while improving the java
integration. An earlier version of this doc suggested that
we would not be considering moving to ASM or Antlr -- but a very
successful Google Summer of Code project and much committer interest
has made it quite likely that we will do just that (move to ASM
and Antlr).

A side goal of Jython 2.5 is to try to get some CPython frameworks working,
especially the web frameworks, for example:

Jython 3.0 (or Jython 3000 to denote the likely year of appearance)
will, like CPython 3.0, be a backwards incompatible version that can
include radical departures from Jython 2.x. The departures will at
least include the departures that CPython 3.0 has made (for example,
old-style classes go away, ints and longs are completely unified,
etc.)

Serious discussions about Jython 3.0 can perhaps begin once CPython 3.0
goes to a GA release.